这个问题通常是由于API Gateway无法正确处理跨域请求而导致的，可以使用以下代码示例来解决问题：

在API Gateway中创建一个OPTIONS方法：

// OPTIONS method for CORS pre-flight request
app.options('/.well-known/openid-configuration', function(req, res) {
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,PATCH,OPTIONS');
  res.header('Access-Control-Allow-Headers', 'Content-Type, Authorization, Content-Length, X-Requested-With');
  res.send(200);
});

然后在路由中添加以下代码：

// GET /.well-known/openid-configuration
app.get('/.well-known/openid-configuration', function(req, res) {
  var options = {
    url: 'https://appleid.apple.com/.well-known/openid-configuration',
    headers: {
      'User-Agent': 'request'
    }
  };

  request(options, function(error, response, body) {
    if (!error && response.statusCode == 200) {
      res.header('Access-Control-Allow-Origin', '*');
      res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,PATCH,OPTIONS');
      res.header('Access-Control-Allow-Headers', 'Content-Type, Authorization, Content-Length, X-Requested-With');
      res.send(body);
    } else {
      console.log(error);
      res.send(500, '{"error": "Error"}');
    }
  });
});

这个代码示例将解决跨域请求和获取Apple的/.well-known/openid-configuration的问题。